This invention relates to an optical scanner and the like. In a conventional optical scanner for documents or graphics, an internal light source is used to project onto a document, and the reflecting light is picked up by a charged coupled device (CCD) for the scanning process. The stability and uniformity of the light source directly affect the scanning quality. This is particularly true for a scanner which has gray-scale or color function. Proper light projection is needed so as to not obscure the signal received by CCD and impair the color tint or illumination level and result in poor scanning quality.
Referring to FIG. 1 for a light source structure of a conventional optical scanner, a lengthy lamp stand (10) is employed to match the size of the scanning documents, lamp stand (10) has a lamp shade (11) which has a reflector (12) disposed inside. The reflector (12) is used for light-condensing or light-compensating for lamp tube (13). However fluorescent lamp tube (13) has a characteristic or deficiency, i.e., it has lower brilliance at the two lateral sides. This deficiency produces uneven brilliance and results in uneven illumination on the scanning document, and consequently impairs the scanning quality.
Therefore, there is still a need for improvements on the light source control in a conventional optical scanner.